SKM 2023 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 8: 2D Materials II (joint session HL/CPP)
HL 8.6: Talk
Monday, March 27, 2023, 16:30–16:45, POT 81
Raman signature of interlayer coupling and lattice dynamics in 2D TMDCs — •Yang Pan1,2 and Dietrich R. T. Zahn1,2 — 1Semiconductor Physics, Institute of Physics, Chemnitz University of Technology, Chemnitz, Germany — 2Center for Materials, Architectures, and Integration of Nanomembranes (MAIN), Chemnitz University of Technology, Chemnitz, Germany
Vertical stacking of two-dimensional (2D) homo- and heterostructures are intriguing research objects, as they are essential for fundamental studies and a key towards 2D device applications. It is paramount to understand the interlayer coupling in 2D materials and to find a fast yet precise characteristic signature. In this work, we report on a Raman fingerprint of interlayer coupling in 2D transition metal dichalcogenides (TMDCs). We observed that the out-of-plane B2g vibrational mode is absent when two monolayers form a vertical stack yet remain uncoupled but emerges after strong coupling. Using systematic Raman, photoluminescence (PL), and atomic force microscopy (AFM) studies of WSe2/WSe2 homo-bilayers and MoSe2/WSe2 hetero-bilayers, we conclude that the B2g vibrational mode is a distinct Raman fingerprint of interlayer coupling in 2D TMDCs. Our further investigations confirmed its applicability on twisted 2D homo- and hetero-bilayers. Our results propose an easy, fast, precise, and reliable measure to evaluate the interlayer coupling and twisting angles in 2D TMDCs.